The Present Invention is directed to the field of process chemical delivery in the electronics industry and other applications requiring high purity chemical delivery. More specifically, the present invention is directed to apparatus and processes for the cleaning of process chemical delivery lines, containers and associated apparatus, particularly during changeout of process chemical or process chemical containers in such process chemical delivery lines.
Evacuation and gas purge of process chemical lines has been used to remove residual chemicals from delivery lines. Both vacuum draw and inert gas purge are successful in quickly removing high volatility chemicals, but are not effective with low volatility chemicals. Safety is a problem when extracting highly toxic materials.
Use of solvents to remove residual chemicals is not new. Various patents have sought to clean systems using solvents, which are hereby specifically incorporated by reference in their entirety herein:
U.S. Pat. No. 5,045,117 describes a method and apparatus for cleaning printed wiring assemblies with a solvent and vacuum action.
U.S. Pat. No. 5,115,576 discloses an apparatus and method of cleaning semiconductor wafers using isopropyl alcohol solvent.
Additional patents regarding solvent cleaning include; U.S. Pat. Nos. 4,357,175, 4,832,753, 4,865,061, 4,871,416, 5,051,135, 5,106,404, 5,108,582, 5,240,507, 5,304,253, 5,339,844, 5,425,183, 5,469,876, 5,509,431, 5,538,025, 5,562,883 and Japanese 8-115886.
Various other prior art U.S. patents are in the same technical field as the Present Invention and are specifically incorporated by reference herein in their entirety:    U.S. Pat. No. 5,472,119—Dec. 5, 1995—Assembly for dispensing fluids from multiple containers;    U.S. Pat. No. 5,398,846—Mar. 21, 1995—Assembly for simultaneous dispensing of multiple fluids;    U.S. Pat. No. 5,297,767—Mar. 29, 1994—Multiple Container Holder;    U.S. Pat. No. 4,570,799—Feb. 18, 1986—Multiple Container Package;    U.S. Pat. No. 3,958,720—May 25, 1976—Adjustable Multiple container dispensing apparatus;    U.S. Pat. No. 5,557,381—Sep. 17, 1996—Develop supplying unit with multiple containers;    U.S. Pat. No. 5,573,132—Nov. 12, 1996—Dispensing Container;    U.S. Pat. No. 5,409,141—Apr. 25, 1995—Two component mixing and delivery system;    U.S. Pat. No. 5,565,070—Oct. 15, 1996—Solvent vapor sucking method and solvent recovering apparatus;    U.S. Pat. No. 4,537,660—Aug. 27, 1985—Vapor generating and recovering apparatus; and    U.S. Pat. No. 5,051,135—Sep. 24, 1991—Cleaning method using a solvent while preventing discharge of solvent vapors to the environment.    U.S. Pat. Nos. 5,964,230 and 6,138,691 both describe a solvent purge technology that uses a special coaxial device to administer solvent to the deadspace above a container of process chemical.    WO 99/64780 describes a solvent purged chemical delivery system which uses three separate sources of purge, including solvent, gases, and hard and Venturi vacuum.
Current systems involving solvent purging of internal plumbing lines are designed to solvent purge extensive portions of the flow lines requiring significant amounts of solvent. In addition, the design of the valves in such systems are not configured to minimize the geometries to be cleaned. These prior art systems require large solvent volumes, excessive cleaning times and complex operations. The present invention, as set forth below, overcomes these difficulties and drawbacks of the prior art by minimizing the flow lines that require solvent purging, providing valve geometries which minimize deadspace and convoluted flow paths, while providing automatic operation with self contained solvent supply and recovery.